a vmg menu can only link to the root menu of a vts
2 ways to handle this:
1: create a transition. Transitions can connect almost anything. To do this with DVD LAB PRO, go to menu --> transtions --> select the kind of transition and which menus to connect.
2: create a new VTS, in which the vts menu you want is is set to root.
or maybe your problem is to set the link correctly:
for DVD LAB PRO:
switch to connections, go to the vmg menu and give it the address of the vts menu as end link. The vmg menu needs to have audio or be a video, so it has an end.